W2 - Glands + Supporting Tissues (lecture) Flashcards
What are glands and what are they involved in?
Invaginations of epithelium, involved in secretion
All glands have a continuous basal rate of secretion, what can change this?
Neuronal/hormonal influences
What are the two components of an exocrine gland?
Secretory component and duct system (branched/unbranched)
What are the 4 ways the secretory component can be structured in an exocrine gland?
Tubular, acinar, coiled or branched
Simple tubular exocrine glands - where are they found and what is the structure?
Large intestine - straight lumen with secretory cells lining entire duct
What is the only example of simple coiled tubular glands and why is a different portion seen in each section taken?
Sweat glands - they coil in 3D
Where are simple branched tubular glands found and what is their structure of tubular portions?
Stomach mucus and there’s multiple tubular secretory portions that come together to form one duct
Endocrine glands lose their connection to the epithelial surface during development, where do they then release their secretions instead?
Directly into the blood
Why are most endocrine glands composed of multiple types of secretory cells?
They release multiple hormones
What 3 things are endocrine glands usually controlled by?
Metabolic factors (e.g.) glucose, NTMs and HMs
Most endocrine glands contain clusters of secretory cells, do they have their own BM or do they share one?
Each cluster has their own
Where do endocrine glands release hormones?
Into intercellular spaces
What is the origin on all supporting tissues?
Mesodermal
What two things make up the supporting tissues?
Specialised cells and extracellular matrix
What makes up the extracellular matrix? (ECM)
Ground substance and fibres
What component of supporting tissues determines it’s physical properties?
ECM
When using H+E, what colour do the fibrous proteins and ground substance stain?
Fibrous - pink, GS - pale/colourless ish
What form is collagen secreted as before polymerisation in the ECM?
Tropocollagen
Type 1 collagen is found in the dermis, tendons and where else? (3)
Ligaments, bone and fibrous supporting tissues
Type 2 collagen is found in hyaline cartilage, how does this appear in ground substance?
As fine fibrils
Type 3 collagen is found in the liver, bone marrow and lymphoid organs, what is their structure and what colour do they appear when stained with silver?
Delicate branching and they stain black
Where does type 4 collagen form a mesh like structure?
Basement membrane
What is it about type 7 collagen that links to basement?
Anchoring fibrils link to basement membrane
What do fibroblasts and myofibroblasts do?
Fib - secrete ECM, myofib - contraction + secretion of ECM
What do chondrocytes, osteocytes and adipocytes do?
Chond - secrete ECM in cartilage, osteo - secrete ECM in bone, adi - store and metabolise fat
Describe the nuclei, cytoplasm and the look of fibroblasts in collagen fibres (when stained)
Nuclei is condensed and elongated, very little cytoplasm, look very dense and pink when stained
Give examples of where loose and dense supporting tissues are found
Loose - bowel submucosa, dense - muscle fascia
What is the interface between support tissues and parenchymal cells?
Basement membrane (BM)
What is the BM called in nerve and muscle tissue?
External lamina
How does the BM regulate maturation?
Is a barrier to downward growth
What three components of BM are made by epithelial cells and which one is made by fibriplasts?
Epithelial cells - collagen 4, entactin + laminin. Fibroblasts - fibronectin
What are the 3 layers of the BM?
Lamina lucida, densa and reticularis
What layer of the BM connects to the epithelial cells and which to the connective tissues?
Lamina lucida - epithelial cells, lamina reticularis - connective tissues
Why does adipose tissue need a rich blood supply?
Important for releasing energy
What do adipocytokines do?
Regulates body mass and influences metabolism
White adipose tissue is typically found in the dermis, what are it’s 2 functions?
THermal insulator and cushioning against shock (e.g. in kidneys)
Why does white adipose tissue stain pale, with very little colour at the edges?
MOstly occupied by lipids, nucleus and cytoplasm is pushed to the edge
Adipocytes have 4 receptors, what for?
Insulin, cortisol, growth hormone and noradrenaline
Brown adipose tissue is found in newborn mammals, what is their role?
Temperature regulation
Brown adipose tissues is arranged in lobules separated by fibrous septae, what is contained in this fibrous septae?
Blood vessels and nerves
